Audio system



FIG. 1 is a front, top and right side perspective view of an audio system, showing our new design;

FIG. 2 is a perspective view thereof as seen from the back, top and left side;

FIG. 3 is a front view thereof;

FIG. 4 is a back view thereof;

FIG. 5 is a top view thereof;

FIG. 6 is a bottom view thereof;

FIG. 7 is a right side view thereof; and,

FIG. 8 is a left side view thereof.

The dotted line portions of the drawings represent environmental structure only and form no part of the claimed design. The broken line showing of numbers, words, and symbols forms no part of the claimed design. 

CLAIM The ornamental design for an audio system, substantially as shown and described. 